Embodiments of the present invention relate to vision correction, and in particular to ophthalmic lenses such as contact lenses, spectacles, intraocular lens, or corneal onlays, for example.
People like to see, and the eye is critical for vision. Vision can include distance vision for viewing distant objects and near vision for viewing near objects. Examples of distant objects can include stars and street signs. Examples of near objects can include printed text of a book or a computer screen, for example. Useful vision can also include central vision and peripheral vision. Central vision can be important for viewing objects with high visual acuity, such as reading signs at night. Peripheral vision can be important for detecting peripheral objects, such as speeding and potentially harmful object coming into the field of view such as a speeding car or a projectile, and the human eye has a wide field of view to sense such objects.
In at least some instances the vision of the eye may be less than ideal and it can be helpful to provide a person with a lens so as to improve vision. For example, spectacles, contact lenses and intraocular lenses can be used to improve vision.
In at least some instances, a component of the eye can become degraded such that replacement of the component can be helpful. For example, the natural crystalline lens of the eye can degrade and may form a cataract such that a patient may receive an intraocular lens (hereinafter “IOL”) to replace the degraded natural crystalline lens.
Although prior IOLs can be used to replace the degraded crystalline lens and improve vision, at least some prior IOLs can be less than ideal in at least some instances. For example, with IOL surgery, a small incision can be made in the eye near the limbus at the periphery of the cornea. The lens inserted through the incision can cause minor distortion of the cornea that may affect patient vision in some instances. For example, the incision near the edge of the cornea may change the shape of the cornea such that the patient vision with the IOL can be less than ideal in at least some instance. Also, the eye may have chromatic aberration and monochromatic aberration prior to incision, and at least some prior foldable IOLs may not be not well suited to correct chromatic aberration or monochromatic aberration in at least some instances.
Although diffractive lenses and Fresnel lenses have been used with prior IOLs, these lenses can produce patient vision that is less than ideal in at least some instances. For example, although diffractive optics can be designed to work well at a specified monochromatic design wavelength, people like to see in color and in at least some instances diffractive optics can scatter light and produce patient perceptible color artifacts at wavelengths away from the design wavelength. Also, diffractive optics can scatter oblique light for peripheral viewing such that peripheral vision with diffractive optics can be degraded more than would be ideal in at least some instances. With Fresnel lenses, images can be degraded and light scatter associated with steps of the Fresnel lens can degrade vision at least partially in at least some instances. Also, oblique light for peripheral viewing can scatter and degrade peripheral vision with Fresnel lenses in at least some instances. Consequently, prior efforts IOLs having diffractive optics or Fresnel lenses have provided less than ideal vision in at least some instances.
In view of the above, it would be helpful to provide improved lenses to correct vision. Ideally such lenses would overcome one or more of the above deficiencies of the prior lenses. For example, a lens that is foldable to a size that fits through a small incision to correct vision with decreased tissue distortion and improved correction of aberrations and improved peripheral vision when positioned would be helpful.